The GeV emission of PSR B1259–63 during its last three periastron passages observed by Fermi-LAT. (December 2018)

• Record Type: Journal Article
• Authors: Chang, Zhi; Zhang, Shu; Chen, Yu-Peng; Ji, Long; Kong, Ling-Da; Liu, Cong-Zhan
• Is Part Of: Research in astronomy and astrophysics. Volume 18:Number 12(2018:Dec.)
• Publication Date: 2018-12
• Subjects: binaries: general -- pulsars: general -- gamma rays: general; Astronomy -- Periodicals; Astrophysics -- Periodicals; 520.5
• DOI: 10.1088/1674-4527/18/12/152
• Languages: English
• ISSNs: 1674-4527

Abstract

Abstract: PSR B1259–63 is a γ -ray emitting high mass X-ray binary system, in which the compact object is a millisecond pulsar. The system has an orbital period of 1236.7 d and shows peculiar γ -ray flares when the neutron star moves out of the stellar disk of the companion star. The γ -ray flare events were firstly discovered by using Fermi -LAT around the 2010 periastron passage, which was repeated for the 2014 and 2017 periastron passages. We analyze the Fermi -LAT data for all the three periastron passages and found that in each flare the energy spectrum can be represented well by a simple power law. The γ -ray light curves show that in 2010 and 2014 after each periastron there are two main flares, but in 2017 there are four flares including one precursor about 10 d after the periastron passage. The first main flares in 2010 and 2014 are located at around 35 d after the periastron passage, and the main flare in 2014 is delayed by roughly 1.7 d with respect to that in 2010. In the 2017 flare, the source shows a precursor about 10 d after the periastron passage, but the following two flares become weaker and lag behind those in 2010 by roughly 5 d. The strongest flares in 2017 occurred 58 d and 70 d after the periastron passage. These results challenge the previous models.